FRIDAY, July 31 (HealthDay News) -- Children as young as 9 years old can and should learn cardiopulmonary resuscitation (CPR), Austrian researchers say.

In a study of 147 students who received six hours of life-support training, 86 percent of the children performed CPR correctly at a follow-up session four months after the training, according to the report published online in the journal Critical Care.

"The usefulness of CPR training in schools has been questioned, since young students may not have the physical and cognitive skills needed to perform such complex tasks correctly," Dr. Fritz Sterz, of the Medical University of Vienna, said in a news release from the journal's publisher.

"We found that, in fact, students as young as 9 years are able to successfully and effectively learn basic life-support skills. As in adults, physical strength may limit depth of chest compressions and ventilation volumes, but skill retention is good," he added.

In the training program, the children were taught CPR, how to use of automatic defibrillators, the correct recovery position and how to call for emergency services. Body mass index, not age, was the major factor in depth of CPR compressions and amount of air exhalation. That means that a well-built 9-year-old child can be just as capable at CPR as an older child, the researchers said.

"Given the excellent performance by the students evaluated in this study, the data support the concept that CPR training can be taught and learned by schoolchildren and that CPR education can be implemented effectively in primary schools at all levels," Sterz and colleagues concluded.